uniform vec4 color;
uniform float diffusePower;
uniform float alphaPower;

czm_material czm_getMaterial(czm_materialInput materialInput) {
  czm_material material = czm_getDefaultMaterial(materialInput);
  vec2 st = materialInput.st;
  float time = czm_frameNumber / 100.;
  float alpha = distance(st, vec2(0.5));
  material.alpha = color.a * alpha * alphaPower;
  material.diffuse = color.rgb * diffusePower ;
  return material;
}